My boyfriend and I were hanging out last night, playing board games with friends, when his heart started to pound really loudly. It wasn t beating faster than usual, just pounding. He had had some coffee early in the morning. Later, as we were driving home, he said it hurt a bit to breathe in, although he could still take deep breaths. When he went to bed last night he said it was pounding and his hands shook. Waking up was fine today, but now his heart is pounding again. He hasn t had any caffeine. He is healthy, fit, drinking water and eating good meals. (He s 20.) Is this just random? Or from eating too much sugar? Should we be concerned?